The present invention relates to composite powder prepared by coating a ramentaceous substrate such as mica with two or more types of coloring layers. Moreover the present invention relates to cosmetic and paint with the composite powder blended therein.
Conventionally ramentaceous substrates such as mica, talc, a and sericite have been blended in cosmetics such as powder foundation or as pearl pigment in various types of paint such as paint for cars. The effect obtained when the ramentaceous powder is blended in cosmetic includes , but not limited to, improvement in the adaptability of the cosmetic to be spread on human skin, improvement of the color pigment of the dispersibility on human skin, and further improvement in the adhesiveness to human skin, and these characteristics are indispensable for make-up cosmetics.
For instance, mica covered with a titanium oxide layer having the certain thickness is called pearl pigment and is used in cosmetic and paint. This pearl pigment varies its color tone at a certain reflection angle against an incidence angle of light according to the thickness of the layer because of optical interference, and has intense luster. The more intense the luster, the more the brightness changes according to a viewing angle, and the characteristic is called flip-flop characteristic.
Colors generated because of the optical interference have the higher brightness as compared to those of general color pigments such as iron oxide red and ultramarine blue, but the tinting strength is very weak. As a method of improving the tinting strength, there has been proposed to cover the titanium oxide layer described above with a metal oxide which absorbs visible light having a wavelength in a certain range such as iron oxide (Refer to Japanese Patent Publication No. 7674/1983). With this method, however, although some particular colors are emphasized and the change in brightness caused by the luster can be made larger, but the effect that the color hue largely changes according to a viewing angle is rather weak.
In some cases, at first mica is covered with ferric oxide and then titanium oxide layer having the certain thickness is formed thereon, but also in this case the effect that the color tone largely changes according to a viewing angle is rather small (Refer to Japanese Patent Laid-Open Publication No. 11161/1995).
Japanese Patent Laid-Open Publication No. 101377/1989 proposes an invention relating to golden color luster pigment which is color and luster pigment containing mica or mica with metal oxide deposited thereon as a substrate and a metal oxide layer containing both titanium and iron coating the substrate, and also in which the metal oxide layer contains pseudo-blockite as an essential component. In this invention, it is described that the metal oxide layer containing, in addition to titanium and iron, pseudo-blockite as an essential component is used for coating the substrate to improve the stability against heat and chemical compounds, and the metal layer is not used for changing the color tone according to a viewing angle.
Japanese Patent laid-Open Publication No. 209024/1996 proposes luster pigment in which a flake-like substrate is sequentially coated with an achoromatic layer having the refractive index of 1.8 or below, a coating layer having the refractive index of 2.0 or more with selective absorbance, and an achromatic or selectively absorptive layer, if necessary, in this order, and there are enlisted aluminum and alloy thereof as the metal substrate; silica, aluminum oxide, and others as the material with the refractive index of 1.8 or below used to form the first layer; and iron oxide, chromium oxide, and titanium oxide (TiO2 reduced with ammonia) as the material having the refractive index of 2.0 or more with selective absorbance. In this invention, the effect that the tone changes according to a viewing angle is pointed out, but in this luster pigment the metal substrate is used to intensify the tone change, and it is described in the publication that the pigment has intense metallic luster. Therefore, with the pigment, it is difficult to obtain cosmetics or paints having modest luster and natural appearance, and its concealing capability is disadvantageously too high.
An object of the present invention is to provide composite powder with the color tone changing according to a viewing angle and insuring natural appearance without excessive luster.
Another object of the present invention is to provide cosmetics and paints capable of emphasizing a face or other solid structures not with change in the brightness, but with change in the hue.
The present invention provides composite powder prepared by coating a ramentaceous substrate with at least two color layers characterized in that a difference between the maximum value and the minimum value of the ab hue angle hab (hMAXxe2x88x92hMIN) as defined in the recommendation on uniform color spaces by CIE (Commission Internationale De L""eclairage) is in the range from 10xc2x0 to 180xc2x0 when this value exceeds 180xc2x0, the value of 360xc2x0xe2x88x92(hMAXxe2x88x92hMIN) is in the range from 10xc2x0 to 180xc2x0), and also that a ratio of the maximum value and the minimum value of the brightness L as defined in the recommendation is in the range from 1.0 to 2.0.
It is preferable to provide a transmission light dispersion layer with the refractive index of 1.3 to 1.8 between the color layers.
Also it is preferable to coat a surface of the composite powder with a reflection and dispersion layer with the refractive index of 1.3 to 1.8 and also having some irregularity on the surface.
Cosmetics and paints according to the present invention have any of the composite powders described above blended therein.
Preferred embodiments of the present invention are described below.
A ramentaceous substrate is used for the composite powder according to the present invention. The ramentaceous substrate includes, but not limited to, natural minerals such as mica, talc, and sericite; and inorganic oxides such as syntheticmica, synthetic sericite, plate-like silica, plate-like aluminum oxide, and plate-like titanium oxide.
An average particle diameter of the ramentaceous substrate is preferably in the range from about 1 to about 100 xcexcm, and more preferably in the range from 5 to 30 xcexcm. When an average particle diameter of the ramentaceous substrate is less than 1 xcexcm, and an average particle diameter of the obtained composite powder is less than 1 xcexcm, change of hue hardly occurs, and on the contrary, when the average particle diameter of the ramentaceous substrate is more than 100 xcexcm, and also the average diameter of obtained composite powder exceeds 100 xcexcm, the luster is so intense that the appearance is unpleasant. The average particle diameter of the ramentaceous substrate as defined herein indicates an average value of the ramentaceous flat surfaces, which is obtained by 100 pieces of ramentaceous substrates with a scan type of electronic microscope for their maximum lengths and calculating the average value. Thickness of the ramentaceous substrate is preferably in the range from 0.05 to 1 xcexcm.
As the color layer used for coating the substrate, known inorganic pigments, organic pigments, inorganic and organic composite pigments may be used, and in addition, coloring matters or a color layer colored with any coloring matter may be used.
More specifically inorganic pigments such as ferric oxide (xcex1-Fe2O3, xcex3-Fe2 O3), oxi-iron hydroxide (FeO(OH)), ferric hydroxide (Fe2 (OH)6), ferrous oxide (FeO), triiron tetraoxide (Fe3O4) titanium oxide containing iron oxide, carbon black, ultramarine blue, iron blue, titanium black, chromium hydroxide, lithium cobalt titanate, manganese violet; organic coloring materials including various types of tar coloring matters, natural coloring matters, and other synthetic coloring matters; and inorganic or organic material layers colored or stained with these inorganic or organic pigments can be enlisted.
There are no limitations as the sequence of lamination, color tone and so on of the color layers on the condition of different color tone each other, and at least two color layers selected likely may be laminated according to the use of composite powder.
In this process, thickness of each color layer is preferably in the range from 5 to 200 nm. When the thickness is less than 5 nm, the tinting power is not sufficient, and on the other hand, when the thickness is more than 200 nm, the feeling in touching is apt to become lower.
Of the sequentially laminated color layers, the first color layer is preferably in the range from 1 to 100 weight portions against 100 weight portions of the ramentaceous substrate, and more preferably in the range from 5 to 40 weight portions. When the quantity is less than 1 weight portion, the tinting power is insufficient, and if the quantity is over 100 weight portions, the adhesion to human skin and the feeling are apt to become lower when used as a component for cosmetics.
The second and subsequent layers are preferably in the range from 1 to 40 weight portions against the 100 weight portions of a ramentaceous substrate with the first color layer or with the first color layer and the transmission light dispersion layer formed thereon described below in the state where other color layer(s) and the transmission light dispersion layer are formed just before formation of the second and subsequent color layer. When the quantity of the second and subsequent layers is less than 1 weight portion, the tinting power is insufficient, and on the other hand, when the quantity is over 40 weight portions, the hiding capability is so strong that colors of underlying layers becomes invisible.
In the composite powder according to the present invention, it is required that a difference between the maximum value and the minimum value of the ab hue angle hab (hMAXxe2x88x92hMIN) as defined in the recommendation on uniform color spaces by CIE (Commission Internationale De L""eclairage) is in the range from 10xc2x0 to 180xc2x0. When the value (hMAXxe2x88x92IMIN) is over 180xc2x0, it is required that the value of 360xc2x0xe2x88x92(hMAXxe2x88x92hMIN) is in the range from 10xc2x0 to 180xc2x0. The value of hat is calculated through the following equation and by using color coordinates a*, b*:
hab=tanxe2x88x921(b*/a*)
The reason the value of (hMAXxe2x88x92hMIN) or 360xc2x0xe2x88x92(hMAXxe2x88x92hMIN) is limited to the above-described range is, when the value is outside the range, the cubic structure can not be emphasized by change in the hue, and a preferable range is decided according to an application of the composite powder. For instance, when used as a component for foundation which is cosmetic, the range from red to blue is preferable, so that the value of (hMAXxe2x88x92hMIN) or 360xc2x0xe2x88x92(hMAXxe2x88x92hMIN) is in the range from 10xc2x0 to 100xc2x0, and when used as a component of paint, the value is set in the range from 10xc2x0 to 180xc2x0.
The difference between the maximum value and the minimum value of hab is described more specifically below. For instance, when mica is used as a substrate, the first color layer is formed with red ferric oxide, and the second color layer is formed thereon with yellow titanium oxide containing iron oxide, yellow becomes stronger around the regular reflection angle, and red brown becomes stronger at farther points from the regular reflection angle. By blending the composite powder having the characteristics described above in cosmetics or paints, solid structure of a face or other physical portions can be emphasized not by change in the brightness, but with change in the hue.
In the composite powder according to the present invention, a ratio of the maximum value vs the minimum value of the brightness L* defined in the Recommendation on Uniform Color Spaces by CIE is required to be in the range from 1.0 to 2.0. The brightness L* is a scale for luster of the composite powder, and when the ratio of the maximum value vs the minimum value of the brightness L* is over 2.0, the luster is so intense that the natural appearance is lost.
The ab hue angle hab and brightness L* are measured using the composite powder spread on adhesive surfaces of a highly smooth transparent double-faced tape adhered onto a white paper piece as a sample and the three-dimensional declination spectrometer (produced by Murakami Shikisai-Gijutsu Kenkyusho, GCMS-4 (based on the double beam system; light source: D65; and view angle: 10xc2x0)), and also by setting the incidence angle at 45xc2x0 and changing the receiving angle from xe2x88x9280xc2x0 to 80xc2x0 at the measurement interval of 5xc2x0. In this present invention, assessment was made by calculating the difference (hMAXxe2x88x92hMIN) between the maximum value hMAX and the minimum value hMIN to hab. Also the assessment was made by calculating the ratio L*MAX/L*MIN between the maximum value L*MAX and the minimum value L*MIN of the brightness L*. As the difference (hMAXxe2x88x92hMIN, between the maximum value hMAX and the minimum value hMIN of hab) is larger, the color changes substantially according to the viewing angle, and as the ratio L*MAX/L*MIN is smaller, the luster is lower.
The composite powder according to the present invention should preferably have at least one transmission light dispersion layer with the refractive index in the range from 1.3 to 1.8 between the color layers. This transmission light dispersion layer disperses the light which has passed through the second color layer (upper layer) and comes into the transmission light dispersion layer, and also disperses the light which is reflected on the first color layer and comes again into the transmission light dispersion layer, so that it provides the effect intensifying the contrast between the color of the second color layer at angular positions near the regular reflection angle and the color of the first color layer at angular positions farther from the regular reflection angle. When the transmission light dispersion layer is not provided, the color of the second color layer at angular positions near the regular reflection angle and the color of the first color layer at angular positions farther from the regular reflection angle are mixed with each other, so that it is hard to obtain sharp contrast.
When the refractive index of the transmission light dispersion layer is not in the above-described range, change of the hue is apt to become smaller. The thickness of the transmission light dispersion layer is preferably in the range from 10 to 50 nm. When the thickness of the transmission light dispersion layer is less than 10 nm, dispersion of light, when passing through the layer, is insufficient, and change of the hue becomes smaller, and on the contrary when the thickness is over 50 nm, feeling in touch of the cosmetics with this composite powder blended therein may become lower. It is to be noted that the quantity of the transmission light dispersion layer is preferably in the range from 1 to 40 weight portions against 100 weight portions of the ramentaceous substrate.
The transmission light dispersion layer is made from an inorganic oxide such as silica, or aluminum oxide, inorganic compounds such as magnesium fluoride, and organic resins such as polyamide, acryl, and polyurethane.
The composite powder according to the present invention should preferably have a reflective dispersion layer formed on the color layer which is the outermost layer and having the refractive index of 1.3 to 1.8 with fine irregularities on the surface. This reflective dispersion layer promotes dispersion of light with the irregularities on the surface thereof, and at the same time suppresses reflection of light on a surface of the particle, thus the effect of lowering the luster being provided. When the refractive index of the reflective dispersion layer exceeds 1.8, change of the hue is apt to become smaller. On the contrary, when the refractive index is less than 1.3, dispersion is insufficient, and the effect of lowering the luster may be insufficient.
Thickness of the reflective dispersion layer is preferably in the range from 10 to 100 nm. When the thickness is less than 10, dispersion of light is insufficient, and the effect of lowering the luster is apt to be insufficient, and on the contrary when the thickness is over 100 nm, the feeling in touch of the cosmetics with the composite powder blended therein becomes poorer, and also change of the hue is apt to become smaller.
A quantity of the light dispersion layer is preferably in the range from 3 to 20 weight portions against 100 weight portions of the composite powder before the light dispersion layer is formed thereon (namely, the ramentaceous substrate with the color layer, or the color layer and a reflective dispersion layer formed thereon).
When the quantity of the light reflection layer is less than 3 weight portions, dispersion of light is insufficient, and suppression of the luster may be insufficient, and on the contrary, when the quantity of the light dispersion layer is more than 20 weight portions, the feeling in touch of the cosmetics with the composite powder blended therein becomes poorer, and also change of the hue is apt to become smaller.
The light dispersion layer is made from an inorganic oxide such as silica or aluminum oxide, an inorganic compound such as magnesium fluoride, or organic resin such as polyamide, acryl, or polyurethane. Silica is especially preferable because it has a lower refractive index, and is adapted to coating.
An average particle diameter of the composite powder according to the present invention is in the range from 1 to 100 xcexcm, and preferably in the range from 5 to 30 xcexcm. The composite powder has a ramentaceous form like the substrate, and the average particle diameter is defined herein as the maximum length of the ramentaceous plane, and is calculated by measuring 100 composite powder pieces with a scanning electron microscope and calculating an average of the maximum lengths of the ramentaceous planes of the particles.
When the average particle diameter of the composite powder particles is less than 1 xcexcm, the feeling in touch may be poor, and on the other hand, when the average particle diameter is over 100 xcexcm, the luster is so intense that the natural appearance is lost. When the composite powder according to the present invention is blended in cosmetics, if the average particle diameter is in the range from 5 to 30 xcexcm, cosmetics with excellent extendability on human skin and good feeling in touch can be obtained.
Further the thickness of the composite powder should preferably be in the range from 0.05 to 1 xcexcm.
The method of producing the composite powder according to the present invention is described below.
Formation of the First Color Layer
To form the first color layer, any known coating method may be employed.
For instance, a metallic salt, an inorganic metal compound, and a partially hydrolyzed material thereof as a precursor of a color layer is added by a specified quantity to a dispersion of a ramentaceous substrate (the solvent is water and/or an organic solvent), hydrolysis or condensation/polymerization is performed under the existence of a catalyst for hydrolysis, if necessary, and the hydrolyte or condensed/polymerized material is deposited on the substrate.
Alternatively, a ramentaceous substrate is dispersed in a dispersion of a metallic salt, a solution of an organic metallic compound, or a partially hydrolyzed material thereof each as a precursor of a color layer, the resultant dispersion is hydrolyzed or further condensed/polymerized under the existence of a catalyst for hydrolysis, if necessary, and the hydrolyte or condensed/polymerized material is deposited on the substrate.
In addition, there can be enumerated the method of having color pigment powder deposited on a substrate by making use of static electricity and heating the deposited matter or the method of forming the first color layer by making use of the mechano-chemical method.
Also a method in which organic resin (monomer or oligomer such as polyamide or acryl is polymerized under the existence of a ramentaceous substrate to form an organic resin layer, and then the organic resin layer is colored with various types of pigments or dyes (coloring matters), or a method in which organic resin (monomer or oligomer) is polymerized with a ramentaceous substrate under the existence of pigments or paints is employable.
Still further a method in which fine particles of organic resin is deposited onto a substrate under the existence of various types of inorganic pigments or organic coloring matters by means of an electrostatic or a mechano-chemical method, or a method fine particles of organic resin is deposited as described above and then melted may be used.
Further a method in which a porous inorganic layer is formed on a ramentaceous substrate and then various types of paints or pigments are impregnated into the pores to form a color layer can be enumerated.
Formation of the Second and Subsequent Color Layers
The second and subsequent layers can be formed with the same method of forming the first color layer excluding the point that the ramentaceous substrate with the first color layer or the first color layer and the reflective dispersion layer formed thereon are used.
Formation of the Transmission Light Dispersion Layer
A known film forming method maybe used to form the transmission light dispersion layer.
For instance, in the case where the transmission light dispersion layer is an inorganic oxide, after the color layer is formed, a metal salt or an organic metallic compound or a partially hydrolyzed material thereof each as a precursor material of an inorganic oxide is added by a specified quantity, and then the added material is hydrolyzed or condensed/polymerized under the existence of a catalyst for hydrolysis, if necessary, and deposited on the substrate to form the transmission light dispersion layer.
When the transmission light dispersion layer is an inorganic compound salt (such as magnesium fluoride), a method in which powder of the inorganic compound salt is deposited on a substrate by making use of the static electricity and then the deposited matter is heated, or a mechano-chemical method may be employed.
Further, when the transmission light dispersion layer is organic resin, a method in which organic resin (monomer, oligomer) such as polyamide, or acryl is polymerized under the existence of a ramentaceous substrate with a color layer formed thereon, or a method in which fine particles of organic resin are deposited by means of the static electricity or a mechano-chemical method.
Formation of the Reflective Dispersion Layer
Also the reflective dispersion layer can be formed in the same way as that for forming the transmission light dispersion layer.
Cosmetics according to the present invention is described below.
In the cosmetics according to the present invention, the composite powder according to the present invention is blended together with various types of cosmetic components.
A blending rate of the composite power is preferably in the range from 1 to 90 weight percent. When the rate is less than 1 weight percent, the effect of providing natural appearance to a target body to be colored is hardly obtained. Namely, with the cosmetics according to the present invention, the hue changes according to a viewing angle, so that a three-dimensional effect can be given to a face or other solid portions of a human body irrespective of change in the brightness. When the blending rate is over 90 weight percent, the tinting power or oily feeling originally required to cosmetics may be lost.
The cosmetic components include, but not limited to, alcohols such as higher fatty alcohols, higher fatty acids, various types including ester oil, paraffin oil, and wax, ethylalcohol, propylene glycol, sorbitol, and glycerin; moisturizing agents such as muco-polysaccharides, collagens, PCA salt, lactates; various types of nonionic, cationic, anionic, or amphoteric surface surfactants; thickeners such as gum arabic, xanthane gum, polyvinyl pyrrolidone, etthylcellulose, carboxyl methylcellulose, carboxyvinyl polymer, denatured or not-denatured clay minerals; solvents such as ethyl acetate, acetone, and toluene; inorganic pigments/dyes; organic pigments/paints; antioxidants such as BHT, tocopherol; water; chemical agents; ultraviolet ray absorber; pH buffer; chelating agents; antiseptics; and perfumes. Further, at least one of inorganic fillers such as silica, talc, kaolin, and mica and physical pigments, and various types of organic resin may be contained therein.
When the composite powder according to the present invention is blended in cosmetics, the surface of the powder may be processed with, for instance, silicone or a fluorine compound.
The cosmetics according to the present invention can be manufactured by a known method, and is used in various forms including powder, cake-like, stick-like, pencil-like, liquid-phase, or cream-like forms, and more specifically the cosmetics include foundation, cream, emulsion, eye-shadow, make-up base, nail enamel, eye liner, mascara, lip stick, pack, and cosmetics for hair.
Paints according to the present invention are described below.
The composite power according to the present invention is blended in the paints according to the present invention together with various types of paint components and various types of solvent components.
The blending rate of the composite powder is preferably in the range from 0.5 to 50 weight percent against the component for formation of paint film. When the blending rate is less than 0.5 weight percent, the natural appearance of the paint film is hardly obtained like in the case of the cosmetics, and on the other hand, when the blending rate is more than 50 weight percent, strength of the paint film may become lower and also flatness of the surface may easily be lost.
The components for formation of the paint film include, but not limited to, organic resin components such as acryl, vinyl chloride, polyurethane, nitrocellulose, and polyester, and inorganic components of metallic alkoxides such as organic titanate, and organic silicate. Further additives such as thickeners, ultraviolet absorbers, and stabilizers, and various types of coloring matters may be used. As solvent components of the paints, such materials as dimethylformamide, methylethylketone, and toluene may be used on the condition that the materials dissolve the components for formation of paint film.